I'm trying to design a mat foundation. When I run the calcs I'm getting this warning as in the pic above. Does anyone know if this is concerning? The deflections are around 0.78" for D+L load case.
If you only provide vertical supports and have any lateral loads the entire mat can slide. This can result in instability or large lateral deformations. https://communities.bentley.com/products/ram-staad/w/structural_analysis_and_design__wiki/3038/ram-instability-in-finite-element-analysis-tn#mat
Seth Thank you! But I don't have any lateral loads applied in the model. Is there a way to check the sliding of the mat ?
You can plot lateral deflection (plan X or Y directions) for any load case or combination.
I am also having receiving this warning message. I modeled and analyzed one mat foundation by importing through RAM SS, where I did not receive this warning message. As I am now analyzing a second mat foundation from this same model, I am receiving this warning. The mat foundations have area springs set up, and have very similar vertical and lateral deflections between the two concept models.
Did you check the lateral deflection, and if so how much is it? Surely your 2 models are different in several ways; the shape of the mat, the magnitude of the lateral load, etc.